Usage of defparameter

Question

I wonder if it is because i do no understand something about the core of the defparameter macro.

So, this gives a weird mistake. I start with:

(defparameter *x* #(1 4 7))
(defparameter *y* #(2 3 55))

Everything's fine but then this:

(defparameter *res* (make-array * :adjustable t :fill-pointer 0))

gives a mistake, which I do not get at all:

 The value                                                                       
 *Y*                                                                           
 is not of type                                                                  
 (OR (MOD 4611686018427387901) CONS NULL)                                      
 when binding SB-VM::DIMENSIONS
    [Condition of type TYPE-ERROR]

Answer 1

* evaluates to the last evaluated value, which is that of the symbol *Y*, which is an array #(2 3 55).

But make-array expects its first argument to specify "dimensions" of the array it creates:

make-array dimensions &key element-type initial-element initial-contents
adjustable fill-pointer displaced-to displaced-index-offset

=> new-array

Arguments and Values:

dimensions---a designator for a list of valid array dimensions.

... a list.

(emphasis mine). Some lists are nulls, some are conses. But not arrays symbols.

And since it expects a list designator, i.e.

a non-nil atom (denoting a singleton list whose element is that non-nil atom) or a proper list (denoting itself),

the other possibility is a whole number.